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RE: Help comparing Rahonavis to modern birds, for school essay



Since no one answered, I'll give it a shot.

The problem is that it's controversial just how Rahonavis relates to birds and 
non-avian dinosaurs.  It's definitely a member of Paraves (closer to birds than 
Oviraptor) and Eumaniraptora (at least as closely related to birds as 
Deinonychus), but past that it gets tricky (well, it's not a troodontid, 
eudromaeosaurian dromaeosaurid or pygostylian bird).  Originally, Forster et 
al. (1998) thought it was an archaeopterygid, which they placed at the base of 
Avialae (closer to birds than Deinonychus) like most authors do.  But they 
noted that making Rahonavis slightly more closely related to modern birds than 
Archaeopteryx is almost as good of an explanation for the data they used.  This 
latter position was recovered in several more analyses, like those of Chiappe 
(2001, 2002) or most of the Theropod Working Group matrices until 2005 (e.g. 
Norell et al., 2001).  It was also found in the more recent analysis in the 
Anchiornis paper (Xu et al., 2008).  However, in 2005 Makovicky et al. 
described Buitreraptor and using another version of the Theropod Working Group 
matrix found Rahonavis to be part of their new group of dromaeosaurids- the 
Unenlagiinae.  Most of the later versions of this matrix have the same result, 
including Senter's (2007) coelurosaur phylogeny paper and Xu et al.'s (2011) 
recent Xiaotingia study that placed archaeopterygids as deinonychosaurs.  
Agnolin and Novas (2011) adjusted the codings of unenlagiines and found the 
group to be in Avialae but further from birds than Archaeopteryx.  So that's 
yet another possibility.  Because all of these studies use slightly different 
combinations of species and characters, we don't know which placement is best 
for Rahonavis.  The fact it switches positions so easily probably means no 
particular one is much better than any other.

I have most of the papers I listed as pdfs, if you want copies.  Just ask!

Mickey Mortimer

----------------------------------------
> Date: Wed, 21 Sep 2011 22:41:43 +0000
> From: yoshi50@comcast.net
> To: dinosaur@usc.edu
> Subject: Help comparing Rahonavis to modern birds, for school essay
>
>
>
> Hello to you all, I need some help with researching for my essay. I need 
> sources to help back up my essay topic. My topic is that birds are in fact 
> dinosaurs and I had to choose three different animals to compare to modern 
> birds. I took Rahonavis as one. What I'm really having difficulty doing is 
> though, finding good sources to back up my claims. I was wondering if anyone 
> here could give me some answers as to how Rahonavis relates to birds and 
> nonavian dinosaurs. This is my first real scientific essay so go esay on me 
> haha!